Battery terminals switched...

I have a 71 Fastback with the boyer ignition and a single coil and the bike has been sitting for a few years. I’m just now getting it going again and as I installed the freshly charged battery, I absent-mindedly connected the terminals incorrectly and heard a POP up under the tank where the coil and the black box are located. The fuse (30amp) on the “negative” terminal was fine but now I get no juice at all. There is no current to the headlight/ammeter which there usually is when the key is turned on. I ran a wire from the battery to the white wire at the boyer to bypass the ignition to check the lights and they work...
Can crossing the terminals do damage to the boyer or coil? If so, how do I check it and how can it be fixed? Any ideas will be most helpful.
Also, the capacitor is disconnected (with the Boyer)...and, is the rectifier needed with the Boyer? It's hooked up now but what I've heard is contradicting and confusing...
Thanks.

Electronics dunn like reverse polarity. I suspect the Boyer is toast. Yes, you need a rectifier no matter what ignition you have (unless you also have an electronic regulator/rectifier unit).

The fuse should have blown instantly if the stock zener diode regulator is still installed. Do you have an electronic regulator in there?

Holeshot said:

I absent-mindedly connected the terminals incorrectly and heard a POP up under the tank where the coil and the black box are located.

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Firstly, was the ignition switched OFF when you connected the battery the wrong way?
If so, then the Boyer ignition and coil should have been isolated, and shoudn't have suffered any damage?

Holeshot said:

The fuse (30amp) on the “negative” terminal was fine but now I get no juice at all.

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This is slightly worrying, as the fuse should have blown if you connected the battery for long enough?

Holeshot said:

There is no current to the headlight/ammeter which there usually is when the key is turned on.

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As the lights worked when you connected a jumper wire between the battery and the white circuit wiring, then the fault is likely to be somewhere between the battery and the ignition switch?

Holeshot said:

ammeter

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I wouldn't expect a '71 model to have an ammeter? Only the pre-'71 models, unless it's been added in which case, the wiring layout is different between the '71-on, and the earlier models?

Holeshot said:

Also, the capacitor is disconnected (with the Boyer)...and, is the rectifier needed with the Boyer? It's hooked up now but what I've heard is contradicting and confusing...

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Possibly you are confusing a Boyer electronic ignition with a Boyer 'Power Box'?
A Boyer Power Box is a regulator/rectifier unit which replaces the standard rectifier and zener diode (and 2MC capacitor), a bike fitted with a Boyer electronic ignition still needs a regulator and rectifier (or a reg/rec unit such as a Power Box).


Connect a jumper between the ammeter terminals, and see what the result is?

Is the 30 amp fuse a modern 30 amp, if so it should be a 15 or 20 amp. The old British fuse was 35 amp intermitant blow or 17 amp continuous, so you need a modern fuse close to 17 amp.

maylar said:

Electronics dunn like reverse polarity. I suspect the Boyer is toast. Yes, you need a rectifier no matter what ignition you have (unless you also have an electronic regulator/rectifier unit).

The fuse should have blown instantly if the stock zener diode regulator is still installed. Do you have an electronic regulator in there?

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I don't have an electronic regulator/rectifier unit just the old original type. The fuse issue has been solved by the latest reply from Kommando from Scotland (see replies)
I do have the stock zener diode as well...

L.A.B. said:

Firstly, was the ignition switched OFF when you connected the battery the wrong way?
If so, then the Boyer ignition and coil should have been isolated, and shoudn't have suffered any damage?

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Yes, is was turned off...this is why it's so frustrating...


The fuse (30amp) on the “negative” terminal was fine but now I get no juice at all.

L.A.B. said:

This is slightly worrying, as the fuse should have blown if you connected the battery for long enough?

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See Kommando's reply...

L.A.B. said:

As the lights worked when you connected a jumper wire between the battery and the white circuit wiring, then the fault is likely to be somewhere between the battery and the ignition switch?

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All the wiring is in very sound condition...are there any components in line from the battery to the switch?...

L.A.B. said:

I wouldn't expect a '71 model to have an ammeter? Only the pre-'71 models, unless it's been added in which case, the wiring layout is different between the '71-on, and the earlier models?

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The bike is actually a combo of '70 & '71 hence the ammeter....


It is definately not the Power box...I'v got the original rectifier and zener.

Holeshot said:

Yes, is was turned off...this is why it's so frustrating...

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The fact that the ignition was switched off at the time is good.

Holeshot said:

All the wiring is in very sound condition...are there any components in line from the battery to the switch?...

The bike is actually a combo of '70 & '71 hence the ammeter....

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As it is a combination of different year parts, then the wiring may not totally conform to either year's wiring spec.?

But it is important to note that the pre-71 model's lighting and horn feed circuits are normally permanently live/hot, as the lighting circuit is connected directly to the battery negative wire before the ignition switch via a three position selector switch in the headlamp, and so the lighting and horn are not controlled by the ignition switch as they would be on the '71-on models.
If that is how it is wired up, then the fault would seem to lie somewhere between the battery and the ammeter Brown/Blue (NU) wire to the ammeter or the Brown/White (NW) between the ammeter and the lighting switch connection White/Brown (WN)? (unless a ground connection failed because of the excess current?) so it shouldn't be too difficult to trace?

Pre-'71 wiring diagram: http://rocbo.lautre.net/technique/norto ... p/149.html
'71-on wiring: http://rocbo.lautre.net/technique/norto ... p/150.html

Double check the fuse. Sometimes those older fuses look to be good, but they've actually come apart inside the end cap. Also, sorry if this sounds patronizing, but check the kill switch position, too.

Holeshot said:

I don't have an electronic regulator/rectifier unit just the old original type. The fuse issue has been solved by the latest reply from Kommando from Scotland (see replies)
I do have the stock zener diode as well...

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The stock bridge rectifier and zener diode connect to the battery before the ignition switch. Reversing the battery has the potential (pun intended) to destroy eiether or both instantly. You should do the electrical checks outlined in the workshop manual on those components.

maylar said:

The stock bridge rectifier and zener diode connect to the battery before the ignition switch. Reversing the battery has the potential (pun intended) to destroy eiether or both instantly. You should do the electrical checks outlined in the workshop manual on those components.

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If either of those two components had failed and gone 'open circuit' it wouldn't stop the lights/horn/ignition from working?
And if either of them had developed a short, then fuses would continue to blow, or the wiring would have burnt out, as apparently the fuse rating was too high (30A continuous, instead of 35A blow -17A continuous)?

shredne said:

Double check the fuse. Sometimes those older fuses look to be good, but they've actually come apart inside the end cap. Also, sorry if this sounds patronizing, but check the kill switch position, too.

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Shredne you are the winner! It was the bloody fuse!! DOH!!! Visually it looked fine but the ohm meter told a different tale...
One good thing with this whole electrical debacle is that I know my bike much more intimately and by going through the entire system I 've discovered many a terminal needing an upgrade...And, I've discovered this wonderful website.
Thanks.